Remote control system



w. BAUGHMAN 2,379,674 REMOTE CONTROL SYSTEM 7 Filed April 24; 1943 ME N Qg U U EQQ Q INVENTOR aaglzman. 611, HIS ATTORNEY Patented July 3, 1945 UNITED STATES PATENT George W. Baughman, Swissvale, Pa; assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application April 24, 1943, Serial No. 484,397 y (cram-s) 14 Claims. My invention relates to remote control systems,

andmore particularly, to centralized trafiic control systems for railroads. In its specific rembodiment, as herein illustrated, my invention has as its principal object the provision of an improved system for the control of amanual block signal governing traffic movements into a stretch of track not equipped with continuous track circuits, and for positively indicating. the .condition of such a signal at a distant control oflice.

A further object of my invention is the provision of an improved system of this character which is adapted to use the line wires of an existing telephone circuit or the like, for the transmission of signal controls andindications reliavbly and economically over relatively long, distances, without interfering with the use of the line wires by other communication facilities.

My system employs code signals of the continuous frequency type possessing a highdegree of immunity. against foreign current interference.

The present invention is an improvement upon that of my prior application for Letters Patent of the United States, Serial No. 400,287, filed June 28, 1941, for Remote control systems.

A feature of my, invention is the utilization of the same line wires to provide communication channels for the transmission of control codes at times and of indication codes at other times, the codes being characterized by the sustained modulation or periodic interruption of the current delivered to the line circuit from a current source indicate its position at the control oflice. The signal may be 'put to stop manually, by opening the line at-the office, or automatically, by opening the line at the station by the operation of a detector track relay, in which case the signal will remain at stop, subject to further manual control, after the controlling track section isvacated.

My invention also includes provisions for obtaining a positive indication of the continuous code type, repeating the stop indication of the signal. a r r I shall describe one form of apparatus s n-- bodying myinvention, and shall, then point out the novel features thereof in claims. I Referring to the accompanying drawingflohe refrence characters I and la designate the rails of a stretch of railwaytrack comprising afman ual block? over which traffic movements are governed by a railway signal S, which as shown, is of the usual color light type. ,It is to beunderstood that except for; a short detector section T having a track relay;'I'R, the stretch of track in advance ;ofsignalS is not providedwith track circuits, and that signal. S is manually cleared or put to stop by the operation of a signal lever V located at a distant control office, and is alsoput to stop automatically, when a train enters the stretch. The reference characters Y and Z designate a pair of telephone line wires or the like :extending from the-central oflice to the station comprising the location of signal. S, which providea, control channel over which signal S is manually governed at times, and at other times provide anindication channel for continuously indicatingits condition at the oflice, and for also indicating when a train it passes the signal as reflected by the release of the detector track relay 'IR. As will be, clear from the drawing, these communication channels include a line battery, 2,

contacts 3 and lot relays QR and QRA, the windings of aline relay LR anda low pass filter 5 at the oflice, linewiresY andZ, and at the station,

the windings 0f asimila r Tfilter 5- and of a line relay LRl, and also the front contact 6, of the trackrelay 'I'Randtheback contact l of a relay QRAJ, all in series. The relaysQRAandHQRAl serve as, switching relays for channel selection,

the control channel includingthe back contacts Q 4 and Land the indication channel thefront contacts 4 and l of these relays. 1 i 3 It is to be understood that suitable local sources ofcurrent are provided atthe ofiice and station for energizing the apparatus, the referi ence character 3 designating the positive or supdition with the line relays LR and LEI steadily,

ply terminal-and (l thenegative or common return terminal of the local source.

*Asshown, lever Y isin its normal or Tstop position,\signalS indicates stop, itsred lamp R being lighted, and the apparatus is in an inactive conenergized; The signalindication lamps GK, YK

and RK, which when the apparatus is active repeatthe indications of the signal, are all dark.

The indication lamp. W is steadily lighted over an obvious circuit including the, lower front contact of relayLR and since the line, circuit inrOFFlCE u eludes front contact 6 of the track relay TR, lamp W indicates that the detector section T is unoccupied.

The signal lever V is to be understood to be of the push-turn type, such as is shown in Letters Patent of the United States to Snavely and Zetwo, No. 2,289,736, issued July 14, 1942, for Circuit controllers; Foran understanding of the present invention it will suffice to :hot that lever V is lockedin each of its three control positions by a spring detent, and can be turned from one control position to another only if the lever is first pressed in an axial direction so as to release selectively lighting the lamps RK, YK and GK to indicate the condition of signal S.

The energization of the decoding transformer by the code operation of the associated line relay the detent and to open contact A, whichecontrols,

a quick release, slow pick-up relay QRLf Relay QR is preferably of a type which assumes'its released position within 0.1 second after its circuit is opened, and has the characteristicthat when its circuit is closed the return of therelay to l-ts energized position is delayed for about 1.2 seconds.

The continuous frequency codes whichmy system employs "consists 'of"-'periodic"interruptions of the line currentat different rates, such as 75,

,120, 180 01:240 times per minute. "These codes are delivered tothe' line by'the periodically operating contacts of one 'or'another of a plurality of continuously active code transmitters, each of which" bears the designation CT'preflxedby a numeral] identifying its rate" of operation" in impulses per minute. As-shown on the drawing three such code transmitters are employed at.

the oflice and'three others at thestationjthese preferablybeing of the type shown in Letters Patent of the United-States No. 1,858,876, issued May 17, 1932, to P. N: Bossart for Coding apparatus} K t The upper front and back oontactof each line relay LR or LRI is effective, when the relay is responding to code, to completecircuits from terminal B alternately in opposi-te directions through'the primary'of a decod'ing 'transformer Bto terminal C, so that current impulses of alternately opposite polarity are generated therein at the code rate and 'deliveredby the upper secondary winding of transformer 8 to a plurality of resonant decoding units DU, each of which is effectiveto selectively energize anassociated decoding relay such as the relay IBOR or IBORl when impulses 'of a particular frequency are supplied thereto. The,v designation of each resonant decoding unit DU and the associateddecoding relay' includes a numericalprefix indicating the ,frequency, in impulses per minuteltc'l which it is responsive.- These decoding units and the circults for the decoding relays are of awell-known type, substantially similar'to those shown in Letters Patent of the United'lstates to l3ossart, No. 1,773,472, issued August 'lQ, 1930, for Railway ,trafiic controlling apparatus, and a detailed description thereof in the present application is deemedunnecessary and l, and the decoding units DU which they control} thus provide means for decodingthe'impulselcurrents supplied to the f line wires, to selectively energize relay 120R, IBUR or 240K, and relay [MRI *or -l80R| according to the frequency of the impulses. The relays IZURI andQlflllR I ,together-withfthe slow release repeating'relay HR which they control, serve as signal control relays'for selectively lighting the lamps R, Y and G qr signal 5, and also 'serveto deternllne the frequency of "the impulse currents by which the relays l 120R, ram and 24m are controlled/the latter serving as indication relays for also induces alternatingcurrent of the corresponding code frequency in its lower secondary winding, which current is rectifiedby the opera- ,tion of the second contact of the line relay to energize a code detector relay CD' or -QDI. The circuits for these relays correspond to those for relay H in Letters Patent of the United States to Nicholson and Allison, No, 2,237,788, issued April 8, 1941, for Railway trafiic controlling apparatus.

The relays CD and CDI are preferably arranged -to pick up at the start of a code having any of the frequencies mentioned, after about 1.5 cycles of operation of the associated line relay, and to release in a period not exceeding one second, after the code operation of the line relay is terminated.

The operation of the system of myinvention under" different assumed conditions will nowbe move'lever V to the center position, asishown, i

or if it is already in that position, he willpress the lever for a brief period, thereby: opening contact A momentarily to release relay QR,'Whih in turn, by opening its contact 9, will release 'a "similar quick release, slow pick-up relay QRA.

'By opening its contact 3, relay QR will release the line relays LR and LRI, and'relayuLR will extinguish lamp W. v

The closing of contact Aupon the release of lever V reenergizesrelay QR, reestablish in'g the line circuit after about 1.2'seconds, andsinc'e back contact 4 of relay QRA is closed, the line circuit now includes the center contact lll'of lever V and contact ll of the code transmitter T. The periodic operation of contact I l effects the transmission of a controlcode by interrupting the line current-delivered by battery 2 at th rate of*'75 impulses per minute, resulting in the energization of the code detector relays'CD and CDI, and causing relays LR. and LRI to be operated periodically tosupply impulses of alternately opposite polarity to the primary windings of their respective transformers 8; The currents thereby induced in the lower secondary windings of transformers 8 are rectified by the relays LR and LRL' about 1.2 seconds after the front contacts of relays CD and CDI close, the switching relay 'QRA and a similar relay QRAI pick up, whereupon the control code is cut off by the opening of back con- (l5- ated by the closing of front contact 1 ofrelay tact 4 of relay QRA and an indication code initi- QRAL- Since the circuit for lamp W is closed each time relay LR picks up, the character of the control code transmitted is indicated by the flashing of lamp W, this lamp remaining dark after relay QRA picks up. l c

After relay QRAI picks up, the line circuit includes.its front contact I, contact I2 of relay CDI, contact l3 of code transmitter MUCT and back contact l5 of relay HR. The indication code transmitted as a result or-the periodic operation of contact l3 therefore has a frequencyof 240 impulses per minute; andit maintains therelays CD'and CDl pickedupandfin addition the code i is supplied overfrontfcontact N5 of relay jQRAto the decoding unit 240DlIto energize theresonant decoding indication relay 240R causing lampyRK to be lighted. Lamp W remains dark, since relays .CD and QRA are bOthpickedllp. i i i I shall next assume that the operator moves lever V to the leftjto cause signal S to indicate caution by the lightingoflampY. The operation of contact A causes relay QR-to release and then pick up as in the first example, releasing relays QRA and 240R in turn, and opening theline for a time sufiicient to release relays CDQCDL and Q AI. When relay QR picks up, a control code of 120 impulses per minute isfdelivered tothe line periodically operating contact H of the office code transmitter IZHCTJ Lamp W flashes at the 120 code rate,and relays SOD andCDI pick up, and

also the control relay I20Rl thereby endrgizing relay HR to light thesignal lamp Y. Then re lays QRA and QRAI pick up to terminat the control codeand initiate an indicationcode of the same frequency, and although the office transmitting contact H is removed from the circuit when relay QRA picks upnthe modulation of the line current continuesat the samerate, due to the insertion of the station;transmitting con tact IS in the circuit whenrel ay QRAE picks up, the line circuit now including front contacts 1 and I2 of relays QRAI and'CDl, the periodically operating contact 18 of the station codeitransmitter IZUCT, back contact Mofrelay 1883i and,

front contact 15 of relayiHR. Those relays already energized remain picked up to maintain the signal lamp Y lighted, and in addition, the indica- 'tion' relay MEDR becomes energized to, light the indication lamp YK, due to the closing of front contact 16 of relay QRA. Relay I'ZilR responds to indication codes only, since" it is controlled over afront contact l6of relay QRA and the control codes aretransmitted over the back contact 4 of relay QRA. i

I shall next assume that the operator moves lever V from left to right to change the indication of signal S frorn caution to proceed, lighting lamp G; The operationof contact A causes relay QR to release andthen pick up as in the-preceding examples, releasing relays QRA and {20R in turn, and opening the linef-ora time suflicient to release relays CD, CDI and QRAI and terminating the delivery of 120 code to relay mm,

which relay also releases, opening the circuit for relayHRfv i w i When relay QR picks up, acontrol code of 180 impulses per minute is delivered tothe line over the right-hand contact ll] of lever V and the periodicallyoperating contact I 9 of the office code der this condition, that is to say, provided the lever contact A is not left open for an'abnormal length of time, thereby avoiding a flash of the red lamp R during a change from caution to pro- When relays QRA and QRAlpick up toter min-ate the 180 controlcode, an indication code ofrthe same frequency is initiated, as in the case of the 120 code already describedthe line circuit now including front contacts ,1 and I! of relays'QRAl and CD1, the periodically operating contact 20 of the stationcode transmitter I80C'I',

and front contacts 14 and 15 of relays IBDRIand over the left-hand contact In of leverV and the i HR. Those relays already energized remain picked up to maintain the signal lamp G, lighted, and in addition, the indication reIay IBGR be" comes energized to light the indication lamp GK.

The operations resulting from a movement of letter V from right to left to change theindication of signal S from proceed to caution are simi A lar to those last described and consequentlya detailed explanation appears unnecessary. 1 i

Assuming that signal S indicates, proceedior caution, it is obvious that it may be returned manually to stop by returning lever V to its center position as shown, contact A then functioning as'in the first example givenl; Signal ,5 is: also arranged to, be put automatically to stop by, a train entering section T, in which'icase the line i circuitgisopened at contact 6 upon the release of the track relay TR, allrof the indication lamps becoming dark under this condition; Whenfthe claim: is:

transmitter l8lICT. Lamp W flashes a the 180 code rate and relays CD and CD! pick up. The

signal control relay 180R! also picks relay HRenergized, lighting lamp G; 1 I

In the foregoing it is to be understood that relay I20Rl will release before relay I80Rl picks up, although these relays have a release period considerably in excess of thatofj relay CDI, due to the energy storage in the rsonant decoding units DU. It follows that in a change of the sigup to hold nal indication T from caution to proceed or from proceed to caution, the energization of relay HR 1 is te'mporarilyinterrupted. RelayuHR isn ade sufficiently slow release toremain picked up untrain vacates section T, contacttcloses, completing the line circuit to cause lamp W to be steadily lighted. The operator will thenrestore lever V- to its center position if he wishes thee-signal to f remain at stop, or will press the lever momen-H:

tarily if he wishes the signalto clearagaimthereby setting the system into operation as already described. It will be seen that ,the clearinguof signal S allows only one train to enter the manual Withinthescope of theappendeclclaimswithout departing from the spirit and, scope of my invention. 1 i Having thus described my invention, what l 1. In a remote control system, an office and a station connected byline wires normally supplied i with line current, means includinga control, lever and a code transmitter at the office for attimes, modulating saidline currentat a given frequency,

a control relay at the station, decoding means at the station selectively responsive to said IinecuI- rent modulated at said give-n frequency for ener gizing saidcontrol re1ay, a normally inactive codetransmitter at the station, switching means at i the office for automatically stopping the modulation of said current by the onice codetransmitter after a time sufficient tceilect the enere gization of i said control relay, and switching means at the station for thenrenderingthe station jcode transmitter efiective if said control relay becomes energized to continue the modulation at said given 'frequency of thefcurrentesup i plied to said line wires to maintainsaidcontrol relay energized.

2- In a remote control system, van'ofiice and a station, a normally closed line circuit extending from the ofiice to the station including a source of current at the ofilce, means including a control lever and a code transmitter at the ofiice for at times modulating the current delivered to the line circuit at a given frequency; a control relay at the station, decoding means at the station selectively responsive to said line-current modulated at said given frequency for energizing the control relay, a normally inactive code transmitter at the station, switching means at the office and switching means at the station, each rendered effective in response to the operation of the ofiice' code transmitter for a' given period of time during whichthe control relay becomes energized, means controlled by the switching means at the office for rendering the oflice code transmitter inactive, and means controlled by the switching means'at the station for rendering the station code transmitter active to continuethe modulation of the line current at said given frequency to maintain said control relay energized.

[3. In a remote control system, an office-and a station,- anormally closed line circuit extending from the office to the station including a-source of current at the office, means including a control lever and a periodically operating contact at said ofiice for at times repeatedly interrupting the lrn'eans atthe station controlled over said line circuit and selectively responsive to said repeatedly interrupted line current for energizing said control-relay, and means including a frontcorn tact of said control relay and a periodically operating contact at said station for at other times "to modulate the current supplied to the line cir cuit for a given period of time, decoding means atth'e station responsive to the modulated current supplied to the line circuit for energizing said control relay, switching means at the station rendered effective by said control relay when energized for causing the station code transmitter to modulate said. current at the end of saidgiven period of time to thereby continue the supply of modulated current to the line circuit to maintain said control relay energized, decoding means at the office responsive to the modulated current supplied by said station code transmitter for e ergizing said indication relay.

5. In a remote control system, an office anda station connected by line wires, a control lever and indication means at the oifice, a plurality of control relays at the station, an indication channel including said line wires and contacts controlled by said control relays', code transmitters at the station adapted to transmit impulses over said indication channel for controlling the'indication means to continuously indicate the condition of said control relays as long as the channel is, established, means responsive to an operation of said-lever from one control position to another for interrupting said indication channel and for then establishing a control channel including with the position to which said lever-is operated,

for a given period of time, and means responsive to said impulses and effective at the end of said given period of time for automatically reestablishing said indication channel; I

6.111 a remote control system, an oflice and a station connected byline wires, a control lever and indication means at the office; a plurality of control relays at the station, an indication channel including said, line wires and contacts controlled by said control relays, code transmitters at the station adapted to transmit impulses over said indication. channel for controlling the indi cation means to continuously indicate the condition of said control relays as long as the channel is established, means responsive to an operation of said lever from one control position to another for interrupting said indication channeland for then establishing a control channel including said line wires and contacts controlled by said lever, code transmitters at the oflice adapted to transmit-impulses over said control channel for operating said control relays selectively in accordance with the position to which said lever is operated, for a given period of time, means responsive to said impulses and effective at the end of said given period of time for automatically interrupting said control channel and for reestablishing said indication channel, and means at the station responsive to the impulses-transmitted over said indication channel for. main: taining said control relays in their last operated positionsas long as said indicationchannel re-' mains established.

"7. In a remote control system, an office and a station connected by linewires,- a control lever and an indication relay at the office,-a control relay at the station, an indication channel including said line wires and contacts closed. when the control relay is energized, acode transmitter at the station adapted to transmit impulses over said indication channel for continuously governing said indication relay'as long as the channel is established, manually operable means at the oldies effective when operated to interrupt said indication channel and tothen establish a control, channel includingsaid line wires, a code transmitter at the office adapted to transmit impulses over said control channel for energizing said control relay in accordance with the position of said control lever, switching relays initially governed over said control channel and efiective after said control relay has been supplied with impulses for a predeterminedv time interval to interrupt the control channel and to establish the I indication channel, and means including the impulses transmitted over'said indication channel for maintaining the control relay energized as long as said indication channel remains established. I

8. In a remote control system, an ofiice and a station connected by line wires, a control lever and an indication relay at the ofiice, a control relayat the station, an indication'channel includingsaid line wires and contacts controlled by the controlrelay, a code transmitter at the station for transmitting impulses over said indication channel. for: governing said indication re- 1251791,??? a co ol anne includin said. li g. W r n sq t of said; co tr l v es p eirsnsmpulsesover mitts-l? at the ofiice for transmitting l a h sai l r a n or ast n sa j yriirq relay slow a tin w maselars ea hs sif c and, t n., s eei r en o ewiq t m.-

lpulses transmitted over said control channel and p r in in, a r le d os tion i to abl sh said control channel and in an operated position togestablish said indicationchannel, means com;

prising a u l y c n roll n c f r main:

ing a front contact of saidslowpick-up relay and said lineywires, a codetransrnitter at the station for transmitting impulses over said indication channel for continuously indicating theposition of said control relay at the oflice as long as said indication channel is established, a control channel including a, back contact of said slow pick-up relay and said line wires, a code transmitter at the ofiice for transmitting impulses over said control channel for governing, saidjcontrol relay in accordance with the position of said control lever, a manually operable contact associated with said lever, a stick circuitffor maintaining said slow pick-up relay normally energized, means responsive to a momentary operation of said manually operable contact for interrupting said stick cir-, cult to release said slow pickup relay and thereby establish said control channel, and means responsive to the impulses transmitted oversaid control channel for reenergizing said slow pick-:up relay to interrupt said control channel after alimited period of time and to then reestablish said indication channel. a l

10. In a remote control system, an office and a station connected by line wires, a control lever and a switching relay at the ofiice, a control relay and a second switching relay at the station, a control channel including contacts of said lever, said line wires and back contacts of said switching relays, means for transmitting impulses over said control channel to operate the control relay in accordance with the positionof thecontrol lever; an indication channel including front contacts of said control relay and of said, switching maintaining the oflice switching relay energized,

and means including the impulses transmitted over said indication channel for maintaining said station switching relay energized subject to control by said manually operable contact.

11. In a, remote control system, an ofiice and a station connected byline wires, a control lever,

a plurality of indication relays and a switching impulse currents of \diiierent frequencies over mecca wi riesw rmers are selectively Eresponsivetifl accordance with the A ontrolled over ,a i w e l f q f a sisi ni impulse c s ver. saidfind q i on ch h r ue srft h ch ch a r l relay is-respqnsiv uchimpulse currents serving to maintain the l relay energized and to fen'ergize th g ndication relay to ,siyetothe'irfipuls A s tra mitted oyersaid fline' w res fer energizi said, sw tching relays to [establish said indication cnaimerarter "said control channel hasbeen established for a given time indication channel to release the station switching relay, but without releasing the office switch (ing relay, and manually operable means for re- 3 leasing the oflice switching relay to initiate the channel. f i

12, In acentralized traffic control system for. railroads, an ofiice and astation connected by a single line circuit normally supplied with line current, a signal lever at the ofiice, a railway signal at the station for governing trafiic move ments into a stretch of track including a detector track section, a track relay for said section hav- 4o ing a front contact in said line circuit, code trans said line currenaaslow pick-up switching relay operation of the control lever for causing the office code transmitter to supply modulated current to theline circuit for agiven period of time only, foroperating saidswitching relay, the rate of modulation of said current being dependent upon the position of said lever, decoding means for causing the code transmitter at the station to modulate said current to thereby continue the operated for indicating the condition of the,

1 a signal.

13. In a centralized trallic control system for railroads, an ofiioe and a station connected by a line circuit normally suppliedwith line current,

code transmitters at the oflice and station for modulating said current, manually operable con. trol means at the ofiice, a, railwaysignal and to energize said switching relay, means ior causing the station code transmitter tomodulate the idi ie l' eenna t se ne e r iiidicateits'posi on ,at hetm e,jrespo a interval, means at the stationfor terminating-the transmission of the impulse currents over said transmission of impulse currents over said control I mitters at theoflice and station formodulating responsive to the rate of modulation of said cur-- rent for selectively clearing said signal, means governed by the signal and rendered effective in response to'the operation of said switching relay a switching relay at the station, meansrespone sive to a momentary operationof said control means for causing the ofice code transmitter to modulate the current supplied to said line circuit current supplied to'the line circuit after said switching relay is energized, at a rate dependent upon the condition of the signal, such modulation railroads, an ofiice and a station connected by a line circuit normally supplied with line current, 'code transmitters at the omce and station for modulating said current,j manually operable control meansfat'the oflice,a'switching relay at the station, a railwaysignal at thestation for governing traffic movements into-astretch of track including a detector track section, a track relay for said section having'a front contact in said line circuit, means responsive "toJthemomentary operation of said control means for causing the ofiice code transmitter to modulate the current supplied to the line circuit for a limited time to energize said switching relay, means controlled by the switching-relay when energized forcausing the station code transmitter to modulate the current supplied to the line circuit at a rate dependent upon the condition of the signal, such modulation being effective to maintain the switching relay energized, signal indication means at the office selectively responsive to the rate of modulation of said current for "indicating the condition of the signal, means for rleasing'said switching relay' to terminate said modulationwhen said line circuit is temporarily opened by said track relay,'and trackindication means at the office responsive to the energized or deenergized condition of the line circuit after said switching relay is released for indicating the condition of said track relay. I

. GEORGE W. BAUGI- IMAN. 

